An overhead traveling crane typically includes generally parallel trucks that run on rails, and a trolley that travels on tracks running between and generally perpendicular to the trucks.
The trolley also usually includes generally parallel trolley sides having wheel shoes to which wheels are connected. The wheels should be aligned with the tracks on which they ride to reduce wear on the wheels. The wheels should also be co-planar to ensure all wheels simultaneously contact the rails.
The trolley also includes mounted objects, such as a motor, a gear case, and a drum or cylinder, which are mounted on generally horizontal support surfaces of support plates. The support surfaces should be substantially level to allow proper mounting of the mounted objects.
A trolley is typically assembled by welding various trolley components together. Welding often causes distortion in the trolley components. Distortion can cause the wheels to be misaligned with the tracks on which they ride, and can also warp the support plates, causing uneven support surfaces.
In a typical overhead traveling crane, the support surfaces and wheel shoes must be machined after trolley assembly to ensure the wheels will be properly level and aligned with the tracks on which they ride when the wheels are connected to the wheel shoes, and to provide a substantially level support surface for the mounted objects. Machining support surfaces and wheel shoes is a time consuming, expensive, and arduous task.